Ultra-long-range Rydberg molecules exposed to a magnetic field

We investigate the impact of an external magnetic field on ultra-long-range and ultracold Rydberg molecules. The Born-Oppenheimer potential surfaces are analysed and discussed for different values of the magnetic field strength. The magnetic field provides an angular confinement turning a rotational degree of freedom into a vibrational one. We explore the vibrational dynamics and observe a pronounced transition in the level spacing from a linear splitting via an irregular regime to a 2D harmonic oscillator-like behaviour. Scaling arguments for the dependence of the potential energy surfaces on the field strengths are provided. The occurrence of a monotonic lowering of the magnitude of the electric dipole moment with increasing magnetic field strength is shown. (letter to the editor)